An effective vaccine able to curb the HIV pandemic is urgently needed but not available and the immunological factors conferring protection are still unclear. Besides T- and B-lymphocytes, natural killer (NK) cells are crucial in the control of viral infections. Recent studies highlight that NK cells, traditionally classified as part of the innate immune system, share features of adaptive immune cells. NK cells might thus be an attractive cell type to be targeted by an HIV vaccine.
NK cells exert various immune functions critical for the control of viral infections, such as cytotoxic effector function and immune regulation through cytokine secretion. To date, five different subsets of peripheral blood NK cells can be distinguished, as defined by their expression levels of CD56 and CD16 (FcγRIII), which are linked to NK cell maturation and antiviral function.
We investigate the kinetics, gene expression profiles and antiviral function of individual NK-cell subsets induced by candidate HIV vaccine regimens. From cryopreserved PBMC of HIV-uninfected study participants in two Phase I/II HIV vaccine trials, we sorted purified NK cells at key time points and integrate our data on kinetics, gene expression and function to define comprehensively how HIV vaccines prime and activate NK cells.